On the domain registrar:1. Setup glue records by specifiying ns1.yourdomain, ns2.yourdomain and point it to your IP address ( where this is possible). Not all registrars allow this.2. But you MUST change the name server to your NS records, as above, ie ns1.yourdomain, ns2.yourdomain

Note this wil be the nameservers as setup in CWP.

Dont reset domains in DO, everything comes from DNS Zone in CWP.

If you do go though Cloudflare, use cloudflare's NS records in point 2 above. CL will then point to your domain